Reciprocating conveyor for transporting heavy cylindrical objects

ABSTRACT

The present invention discloses a lift-table flatcar conveyor for transferring a roll ( 3 ) or, respectively, group of rolls of cardboard, cellulose or paper from a first station to a second station, the lift-table flatcar conveyor comprising a rail ( 2 ) arranged between the first station and the second station and, arranged back-and-forth movable along the rail ( 2 ) between the first station and the second station, a flatcar ( 1 ) onto which the roll ( 3 ) or, respectively, a group of rolls is movable. During the transfer operation, the roll ( 3 ) or, respectively, the group of rolls moved onto said flatcar ( 1 ) is supported by support means ( 4 ) that are adapted rotatable for the duration of the return travel of the flatcar ( 1 ) from the second station to the first station into a home position, wherein the support means ( 4 ) can pass rolls ( 3 ) waiting on the stations without making a physical contact with the rolls.

[0001] The present invention relates to a lift-table flatcar conveyoraccording to the preamble of claim 1.

[0002] The invention also relates to a method for transferring rolls orroll groups by means of a lift-table flatcar conveyor.

[0003] Rolls coming from a papermaking machine are slit at aslitter-winder into rolls of narrower width according to customer order,followed by packaging of the rolls at a packaging machine. During thepackaging operation, the roll ends are first provided with inner headersand next a sufficient number of convolutions of a wrapper material iswound about the roll on the wrapper station of the packaging machine,whereupon the overlap portion of the wrapper is draped over the innerheaders placed on the roll ends. In some instances, a number of wrappermaterial convolutions is first wound about the roll, followed by theinsertion of the inner headers into the tubes formed by the wrapperoverlap at the roll ends and the wrapper rims are next draped over theinner headers. Generally, an outer header is attached by hot-meltglueing onto the draped wrapper rim and the inner header at the endplaten press of the packaging machine.

[0004] The widths of the narrowest customer rolls coming from theslitter to the packaging machine vary in the range of 100-500 mm. Forinstance, in mills making fine paper grades, the roll widths of narrowrolls are typically from 180 mm to 400 mm, in cardboard mills from 350mm to 500 mm and in the manufacture of roll cores from 100 mm to 300 mm.Narrow rolls are packed either individually wrapped or, typically, astwo- or multi-roll packs containing 2-4 rolls bunched end-to-end. Thecustomer rolls to be packaged in two- and multi-roll packs are normallywrapped together immediately after they leave the slitter, because theirhandling and carrying in bundled form is much easier.

[0005] The rolls to be packaged can be transferred from one station ofthe packaging machine to another using a lift-table conveyor in which asingle roll or a group of rolls is placed on a flatcar that movesbackward and forward along a long track between two successive stationsof the packaging machine. Herein, a roll resting on the support rolls ofthe first station is moved uphill along the track and by way of liftingup the platform table of the flatcar, whereupon the roll can be moved tothe second station on the flatcar. Subsequently, the roll is deliveredonto the support rolls of the second station by lowering both the trackand the platform table. Finally, the flatcar is returned to the firststation to fetch the next roll. The roll being transferred is placed onthe flatcar so that the center axis of the roll is aligned parallel tothe travel direction of the flatcar, which means that the roll canreadily topple when the flatcar accelerates or decelerates its speed.The risk of roll toppling is particularly imminent when narrow rolls arebeing transferred by fast conveyors. It may also happen that narrowrolls at the ends of a roll group fall sideways during the transferoperation. Obviously, the problem can be eliminated by reducing theacceleration or deceleration rate of the flatcar units. This, however,also reduces the throughput capacity of the roll packaging machine.

[0006] It is an object of the present invention to provide an entirelynew type of lift-table flatcar conveyor and a method for transferringrolls or roll groups on a lift-table flatcar conveyor so that theabove-mentioned complications are overcome.

[0007] The goal of the invention is achieved by way of providing thelift-table flatcar conveyor with support means such as support arms thatsupport the roll or roll group being transferred and keep the sameupright during the transfer operation. The support arms are arranged topress against both ends of the roll or roll group during transfer.During the return travel of the conveyor flatcar, the support means arerotated into a home position, wherein they can move without the risk ofa physical contact past rolls or roll groups resting on the stations ofthe packaging machine. Advantageously, the home position of the supportarms is such that the arms are rotated downward in a position parallelto the tracks, whereby the arms can travel below the rolls resting onthe stations at a level which is lower than that on which the rolls areresting. Further advantageously, the support means are integrated withthe construction of the lift-table flatcar traveling between thestations of the packaging machine.

[0008] More specifically, the lift-table flatcar conveyor according tothe invention is characterized by what is stated in the characterizingpart of claim 1.

[0009] Furthermore, the method according to the invention fortransferring rolls or roll groups on a lift-table flatcar conveyor ischaracterized by what is stated in the characterizing part of claim 8.

[0010] The invention offers significant benefits.

[0011] By virtue of the invention, the capacity of a roll packagingmachine increases substantially because rolls can be transferred withoutthe risk of toppling at an increased speed between the stations of thepackaging machine. A lift-table flatcar conveyor according to theinvention is capable of safely transferring in an upright position rollsabout 150 mm wide, while transfer systems lacking support means cantransfer at a comparable speed only rolls having a width of about 400 mmor wider. During the return travel of the conveyor flatcar, the supportarms are arranged to move past the rolls or roll groups resting on thestations of the packaging machine. Advantageously, the home position ofthe support arms is such that the arms are rotated downward in aposition parallel to the tracks, whereby the arms can travel below therolls resting on the stations at a level which is lower than that onwhich the rolls are resting and, thus, do not need any clearance to beprovided on the sides of the conveyor track. Moreover, the support meansaccording to the invention have a simple construction and can beretrofitted on existing lift-table flatcar conveyor, too.

[0012] In the following, the invention will be examined in greaterdetail with the help of exemplifying embodiments and making reference tothe appended drawings in which

[0013]FIG. 1 shows a side view of an embodiment of the lift-tableflatcar conveyor according to the invention with the support means setin their supporting position.

[0014]FIG. 2 shows the lift-table flatcar conveyor of FIG. 1 with thesupport means set in their home position for the return travel of theflatcar.

[0015]FIG. 3 shows the lift-table flatcar conveyor of FIGS. 1 and 2 withthe support means set in their different positions.

[0016] The number of flatcars in a lift-table flatcar conveyor system istypically 3 to 5, advantageously one less than the number of stations inthe packaging machine, whereby each track connecting two stations isused by one flatcar. Generally, the flatcars are connected to each otherand move backward and forward between the stations, which means that thedistances between neighboring stations must be equal. The last stationof the packaging machine normally has no rolls when the transfersequence of the flatcars 1 is started. The rolls are moved on theflatcars 1 with the rails 2 and the lift-table flatcars 1 driven intotheir upper position, while the return of the flatcars 1 takes placewith the rails 2 and the flatcars 1 driven into their lower position.Prior to the arrival of a new roll, the roll resting on the last stationof the packaging machine is moved from the station onto a ramp by meansof a pusher, for instance.

[0017] As shown in FIG. 1, the flatcar 1 of the lift-table flatcarconveyor is arranged to move along a linear track such as rails 2between a first station and a second station of a roll packagingmachine. Roll 3 resting on support rolls on the first station of thepackaging machine is elevated upward by lifting the rails 2 and theflatcar 1 by means of lift cylinders and levers, whereupon support arms4 mounted on the flatcar 1 are rotated into supporting positions againstboth ends of the roll 3. Subsequently, the flatcar 1 with the roll 3resting thereon supported by the support arms 4 is transferred along therails 2 to the second station of the packaging machine. The roll 3 beingtransferred is placed on the flatcar 1 so that the center axis of theroll is parallel to the travel direction of the flatcar 1.

[0018] On the second station of the packaging machine, the support arms4 are released and rotated downward into their home position parallel tothe rails 2 as shown in FIG. 2 for the return movement of the flatcar.Next, the flatcar 1 and the rails 2 are lowered, whereby the roll 3remains resting on the support rolls of the second station.Subsequently, the flatcar 1 is returned along the rails 1 back to thefirst station. During the return movement of the flatcar, the supportarms 4 in their home position can pass from under the roll 3 transferredonto the support rolls of the second station and the new roll nowwaiting on the support rolls of the first station without making aphysical contact with either of the rolls, since the arms travel belowthe horizontal level defined by the rolls. Next, the new roll resting onthe support rolls is elevated through lifting the rails 2 and theflatcar 1 running thereon by means of lift cylinders and levers,whereupon support arms 4 are rotated into supporting positions againstboth ends of the new roll. If the new roll resting on the first stationcannot be transferred immediately to the second station, the transfercycle time may anyhow be optimized shorter by moving the support arms 4close to the ends of the new roll, whereby only a short final movementis needed to drive the support arms 4 into their supporting position.The new roll thus secured is moved onto the support rolls of the secondstation similarly as the preceding roll 4.

[0019] The construction and movements of an embodiment of the lift-tableflatcar conveyor according to the invention between its supporting andreturn positions is shown in more detail in FIG. 3. The support arm 4adapted to press against the roll end is pivoted rigidly on a base 6that moves driven by a circulating-ball screw connected to a motor 7. Toboth sides of the flatcar 1 are mounted guiding surfaces such as guidetracks 8 along which wheels 9 mounted on the base are arranged to run.The support arm 4 is mounted on bearings on a shaft connecting thewheels 9. If the load imposed on the support arm 4 becomes too high, asafety pin 10 connecting the support arm 4 to the base 6 breaks, wherebythe support arm 4 can swing about its pivot point 11. Mounted on thesupport arm 4 is a sensor 12 that senses the support arm 4 havingreached the end of the roll or, respectively, group of rolls to betransferred. The support arm 4 is further provided with a limit sensorsenses the support arm 4 having reached its retracted home position forthe return movement of the flatcar. The electrical cables of the flatcar1 are placed in an articulated chain 13 protecting the cables during thehorizontal movement of the flatcar.

[0020] When the base 6 is moved by the motor 7 and the circulating-ballscrew connected thereto, the wheels 9 run along the guide tracks 8. Thesupport arm 4 moves from its horizontal home position into its verticalsupporting position when the wheels 9 move upward along the slantedportions of the tracks 8. Next, the wheels 9 run along the horizontalportions of the tracks 8 toward the roll or, respectively, roll group tobe transferred. The movement is stopped when sensor 12 detects thesupport arm 4 to rest against the roll or, respectively, roll group tobe transferred. The return movement from the supporting position intothe home position takes place in the reverse order.

[0021] In addition to those described above, the invention may havealternative embodiments.

[0022] For instance, the support arm 4 may be arranged to support onlyone end of the roll 3. The transfer of the roll 3 or, respectively, rollgroup from the support rolls to the flatcar 1 and, respectively, fromthe flatcar 1 onto the support rolls may also be implemented by alifting/-lowering movement of the support rolls. If a sufficientfootprint is available on the sides of the conveyor, the rotation of thesupport means 4 into their home position for the return travel of theflatcar may also be arranged to take place to the sides of the flatcar.

What is claimed is:
 1. Lift-table flatcar conveyor for transferring a roll (3) or group of rolls of cardboard, cellulose or paper from a first station to a second station, the lift-table flatcar conveyor comprising a rail (2) arranged between said first station and said second station, arranged back-and-forth movable along said rail (2) between said first station and said second station, a flatcar (1) onto which said roll (3) or group of rolls is movable so that the center axis of said roll (3) or group of rolls becomes parallel to the travel direction of said flatcar (1), and support means (4) for supporting said roll (3) or group of rolls moved onto said flatcar (1) during transfer on said flatcar, said support means (4) being rotatable for the duration of the return travel of said flatcar (1) from said second station to said first station into a home position, wherein said support means (4) can pass rolls (3) waiting on said stations without making a physical contact with said rolls, characterized in that said support means (4) are arranged to press against both ends of said roll (3) or group of rolls during the transfer operation.
 2. Lift-table flatcar conveyor according to claim 1, characterized in that said support means (4) are during said return travel of said flatcar rotated into a downward position that is parallel to said track (2) thus allowing said support means to travel past said roll(s) (3) waiting on said station so as to pass the rolls below the horizontal level defined by said rolls.
 3. Lift-table flatcar conveyor according to claim 1 or 2, characterized in that said support means comprising support arms (4) adapted to press against both ends of said roll (3) or group of rolls to be transferred.
 4. Lift-table flatcar conveyor according to any one of foregoing claims 1-3, characterized in that said support means (4) are adapted onto said flatcar (1).
 5. Lift-table flatcar conveyor according to claim 4, characterized in that said support means (4) are adapted to move along a guide track mounted on said flatcar (1).
 6. Lift-table flatcar conveyor according to claim 1, characterized in that said first station and said second station include support rolls on which said roll (3) or group of rolls being transferred can be placed.
 7. Lift-table flatcar conveyor according to claim 6, characterized in that said rail (2) and said flatcar (1) are arranged movable in the vertical direction for elevating said roll (3) or group of rolls being transferred off from said support rolls and, respectively, for lowering the same onto said support rolls.
 8. Method for transferring a roll (3) or group of rolls of cardboard, cellulose or paper from a first station to a second station by means of a lift-table flatcar conveyor comprising a rail (2) arranged between said first station and said second station and, a flatcar (1) arranged back-and-forth movable along said rail (2) between said first station and said second station, the method comprising the steps of moving said roll (3) or group of rolls on said first station onto said flatcar (1) so that the center axis of said roll (3) or group of rolls becomes parallel to the travel direction of said flatcar (1), moving said flatcar (1) to said second station, supporting said roll (3) or group of rolls during the transfer operation by support means (4), removing said roll (3) or group of rolls from said flatcar (1) on said second station, returning said flatcar (1) from said second station to said first station, and rotating said support means (4) for the duration of the return travel of said flatcar (1) from said second station to said first station into a home position, wherein said support means (4) can pass rolls (3) waiting on said stations without making a physical contact with said rolls, characterized in that said support means (4) are arranged to press against both ends of said roll (3) or group of rolls during the transfer operation.
 9. Method according to claim 8, characterized in that said support means (4) are during said return travel of said flatcar kept rotated into a downward position allowing said support means to travel past said rolls (3) waiting on said station so as to pass the rolls below the horizontal level defined by said rolls.
 10. Method according to claim 8 or 9, characterized in that said support means are formed by support arms (4) adapted to press against both ends of said roll (3) or, respectively, group of rolls to be transferred.
 11. Method according to any one of foregoing claims 8-10, characterized in that said roll (3) or, respectively, group of rolls is supported by both ends by said support means (4) during the transfer operation.
 12. Method according to claim 8, characterized in that said first station and said second station include support rolls on which said roll (3) or group of rolls to be transferred are placed.
 13. Method according to claim 12, characterized in that said rail (2) and said flatcar (1) are moved in the vertical direction for elevating said roll (3) or group of rolls off from said support rolls and for lowering the same onto said support rolls. 